Seeking solutions

Tuesday

May 14, 2013 at 9:50 AMMay 14, 2013 at 12:28 PM

A team of University of California, Davis, scientists – in cooperation with the Scott Valley Groundwater Advisory Committee – is developing a groundwater management tool that could lead to better stream flow conditions in Scott Valley.

John Bowman

A team of University of California, Davis, scientists – in cooperation with the Scott Valley Groundwater Advisory Committee – is developing a groundwater management tool that could lead to better stream flow conditions in Scott Valley.

A recent press release from UC Davis explained that their hydrologic modeling tool could help inform decision-makers and regulatory agencies involved in the issue of balancing salmon protection and water management along the Scott River.

While the Scott River watershed contains habitat critical to several species of salmon and trout, it also supports an agricultural economy composed of family farms and ranches raising hay, pasture and cattle.

"Regulatory agencies, farmers, ranchers and the local community are working to find win-win solutions for both fish habitat and agriculture," stated the release.The groundwater committee was created and appointed by the Siskiyou County Board of Supervisors in 2011 to make recommendations to the supervisors about managing groundwater in the Scott Valley and to comply with state efforts to improve conditions in the watershed.

The North Coast Regional Water Quality Control Board requested that Siskiyou County develop a groundwater study plan to understand how surface water might be made cooler through connections with groundwater. The groundwater committee, as well as the Scott River Watershed Council and the Siskiyou Resource Conservation District, have been working with scientists for several years to better understand the movement and use of water in Scott Valley in order to reach lasting solutions.

The 57-mile-long undammed Scott River is a tributary of the Klamath River, and portions of it are designated as a federal and state Wild and Scenic River. "For most other rivers in California, summer and fall water flows are entirely dictated by dams that have water behind them," said Thomas Harter, a UC Davis Cooperative Extension groundwater hydrologist in the Department of Land, Air and Water Resources who led studies of Scott Valley groundwater. "Scott River is very dependent on the groundwater system," he said.

A combination of irrigated agriculture in Scott Valley, a lack of streamside shade on the river, and climate change has led to warmer river temperatures and reduced late summer and fall stream flows on the river, particularly in dry years, Harter said.

The Scott Valley community is working to address watershed issues in a variety of ways, including riparian management and the recent development of a groundwater management plan by the groundwater committee.

In a recent report to the North Coast Regional Water Quality Control Board, UC Davis researchers summarized the hydrology of the Scott Valley for the past 21 years. Harter will combine this information into an integrated hydrologic model, expected to be complete in early 2014.

UC Davis says their tool will be used to evaluate future groundwater management scenarios, which could include: How do irrigation management practices affect flow and temperature in the river? What are the effects of allowing for more beaver dams? How can additional water recharge during spring and early summer be used to support the aquifer during the critical late summer period?

"The local community and other stakeholders have a number of ideas on groundwater management that could benefit the stream flow," Harter said. "This hydrologic model will provide the physical framework to evaluate those ideas. It will provide guidance on the possible direction that groundwater management can take in the Scott Valley."

UC Davis says the hydrologic modelling tool can help provide science-based answers for resource managers grappling with a changing climate and a changing river.